Abstract

ZnO single-crystalline nanowire-type nanostructures were synthesized on silicon by thermal chemical vapor deposition without catalysts through a two-step pressure-controlled vapor-reflected process at a low temperature of 550 °C where self-organized hexagonal crystalline or porous nanowire arrays were grown on nanorods. The nanowire diameter is around 20 nm and number of nanowires is selected by the nanorod size. Cathodoluminescencespectra exhibit strong green emissions, indicative of high oxygen-vacancy density, which sheds a light on further applications for multichannel nanoconductors in nanodevices.

The work was supported by Research Grant No. NSC93-2120-M-006-007, National Science Council of Taiwan. The authors are grateful to Professor K. H. Chen, Professor L. C. Chen, and C. W. Hsu for the CL experiments and helpful discussions. The authors thank the Center for Micro/nano Technology Research, National Cheng Kung University, Taiwan for the provision of the HRTEM.